Renesas X5045S8-2.7

Overview

X5045S8-2.7 from Intersil (now Renesas) is a CPU supervisor IC integrating power-on reset, watchdog timer, supply voltage supervision, and 4Kbit SPI EEPROM in an 8-lead SOIC package. It operates from 2.7V to 5.5V, features a factory-programmed 2.93V reset threshold (±2.5%), supports 3.3MHz SPI communication, and delivers 1M write-cycle endurance with block-lock memory protection - used for firmware parameter storage and brownout recovery in embedded controllers.

For engineers reviewing the X5045S8-2.7 datasheet, X5045S8-2.7 pinout, X5045S8-2.7 application, or X5045S8-2.7 equivalent, key selection criteria include its dual-role CS/WDI pin, reprogrammable VTRIP capability, active-low RESET output with 200ms timeout, and compatibility with microcontroller SPI interfaces requiring low-power standby current (<10µA watchdog off).

Technical Context

The X5045S8-2.7 implements a dedicated analog voltage monitor with hysteresis for precise VCC supervision and a nonvolatile watchdog timer controlled by status register bits WD0/WD1. Its reset assertion logic combines power-on reset (tPURST = 200ms typ), undervoltage detection (VTRIP = 2.93V), and watchdog timeout (200ms/600ms/1.4s or disabled).

Internally, it integrates a 512 × 8-bit SPI EEPROM using Direct Write™ technology, supporting 16-byte page writes with 5ms typical write cycle time and block lock protection configurable via BL0/BL1 bits. The device uses a single SPI bus (CS/WDI, SI, SO, SCK, WP, VCC, VSS, RESET) with push-pull SO and open-drain RESET outputs.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (Small Outline Integrated Circuit), RoHS-compliant, Pb-free plus anneal finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar CPU supervisor with EEPROM applications.

Compared with MAX6816EPA+ and MCP9800T-E/MS, the X5045S8-2.7 uniquely integrates reset, watchdog, and EEPROM in one SOIC-8 device - reducing component count, PCB area, and qualification effort for embedded systems requiring coordinated power management and parameter persistence.

Availability

X5045S8-2.7 is available at Aetrix Electronics and suitable for industrial process controllers, network routers, medical infusion pumps, and smart energy meters requiring stable component supply with long-term lifecycle support.

Supply support for X5045S8-2.7 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics (formerly Intersil) is a global semiconductor leader specializing in microcontrollers, analog, and power management solutions for industrial, automotive, and communications markets.

The X5045 family was designed to consolidate system supervision and nonvolatile storage into a single SPI-compatible device - targeting cost-sensitive, space-constrained embedded applications needing high reliability and field-programmable voltage thresholds.

FAQ

What is the default watchdog timeout setting for the X5045S8-2.7?

The X5045S8-2.7 ships with watchdog timer disabled (WD1=1, WD0=1). This factory-default state prevents unintended resets until the host MCU explicitly configures the timeout period via the WRSR instruction. Once programmed, the watchdog setting persists across power cycles due to nonvolatile status register storage, and remains active even after full power loss.

Can the reset threshold voltage of the X5045S8-2.7 be changed after soldering?

Yes, the X5045S8-2.7 supports in-system VTRIP reprogramming using a 15–18V pulse applied to the WP pin while issuing specific SPI commands (WREN followed by write to address 01h). This allows field calibration to match actual board-level supply tolerances without replacing the component. The procedure requires no special equipment beyond standard SPI programming infrastructure.

How does the X5045S8-2.7 handle simultaneous write protection from both software and hardware?

The X5045S8-2.7 enforces hierarchical write protection: when WP is held LOW, all nonvolatile writes (EEPROM and status register) are blocked regardless of WREN latch state or BL0/BL1 settings. Software-based protection (WREN + block lock bits) only takes effect when WP is HIGH. This dual-layer scheme ensures robust defense against accidental or malicious overwrites in mission-critical systems.

What is the maximum SPI clock frequency supported by the X5045S8-2.7?

The X5045S8-2.7 supports a maximum SPI clock frequency of 3.3MHz across its full 2.7V–5.5V operating range. This rate is specified under DC electrical conditions with SO loaded at 2mA and applies to all operations including READ, WRITE, RDSR, and WRSR. Timing margins remain compliant down to 1.8V VCC per VOH2/VOH3 specifications.

Does the X5045S8-2.7 require an external pull-up resistor on the RESET pin?

Yes, the X5045S8-2.7 features an open-drain RESET output and requires an external pull-up resistor (typically 4.7kΩ to VCC) to assert a valid logic HIGH when inactive. This configuration allows wired-OR connection with other reset sources and ensures proper voltage level translation across mixed-supply systems. The RESET pin actively pulls LOW during power-up, brownout, or watchdog timeout.